A conservative group is calling on the Senate ethics committee to examine nine top Democrats, accusing them of pushing the IRS to investigate specific groups.

The Center for Competitive Politicsannounced their complaint Tuesday, in which they charge that lawmakers tried to get the tax agency to probe outside conservative groups.

“These senators improperly attempted to use the IRS to suppress the free speech of American citizens for their party’s electoral gain,” said Brad Smith, chairman of the Center and a former Chairman of the Federal Election Commission. “We will fight this type of abuse of power and work to ensure that those who have violated Senate Ethics rules are held to account.”